Most cases of leukemia are completely cured at present; however, many cases of intractable (treatment-resistant) leukemia still exist. For example, it is known that an MLL (myeloid/lymphoid or mixed-lineage leukemia) gene is located on chromosome 11 (11q23) and fuses with a gene such as AF4, AF9 and ENL through chromosomal translocation to cause leukemia. Leukemia having MLL gene rearrangement (MLL) is a typical case of intractable leukemia. MLL is known as fetal leukemia since many affected infants experience recurrence and die. The three-year survival rate is only 30% and two out of three patients die. In addition, most of MLL cases develop during infancy (up to one year old). From this, development of a therapy for MLL has been desired.
In childhood leukemia, more than half of patients experience recurrence, leading to outcome of death. To overcome the disease, many pediatricians apply currently available drugs in combination for treatment; however, it is extremely difficult to completely cure the disease.
In treatment of leukemia, the recommended therapeutic drug varies depending upon the type of leukemia and differs individually depending on the stage of treatment (remission induction therapy, maintenance therapy). For example, in a remission induction therapy for pediatric acute lymphatic leukemia, a steroidal anti-inflammatory drug such as prednisolone or dexamethasone is used.
Recently, a pharmaceutical composition having an effect for suppressing proliferation of leukemia stem cells and being effective in treating or suppressing recurrence for acute myeloid leukemia (AML) is disclosed (Patent Literature 1, and Non Patent Literature 1).